package com.idheima.zuoye.zuoye2;

public class Test {
    public static int sum(int n) {
        if (n == 10) {
            return 1;
        }
        return (sum(n + 1) + 1) * 2;


    }

    public static void main(String[] args) {
        int sum1 = sum(1);
        System.out.println(sum1);
    }
}
